NEW YORK — Former CIA Director George Tenet’s defense of his agency’s performance in the lead-up to the war in Iraq will echo from now through Election Day next year, but other disclosures in his new book are equally sobering and, in laying out the scope of al-Qaida’s ambitions, sometimes far more frightening.

The book, “At the Center of the Storm,” which is being published Monday, reveals that al-Qaida or groups affiliated with it have undertaken several other operations aimed at equaling or even surpassing the carnage of the Sept. 11, 2001, terrorist attacks.

The operations, which either were thwarted by authorities or were canceled for one reason or another, included efforts to assassinate Vice President Al Gore with anti-tank missiles during a trip to Saudi Arabia, release cyanide in the New York subway system and procure weapons of mass destruction, including nuclear weapons, from Pakistani nuclear scientists.

In one especially chilling assertion, Tenet reveals that several intelligence sources were indicating in fall 2001 that a small nuclear weapon may have been smuggled into the United States.

The plot to kill Gore
Tenet discloses that in 1998, Saudi officials foiled a plot by Abdel Rahim al-Nashiri to smuggle four Sagger anti-tank missiles from Yemen into Saudi Arabia a week or so before Gore was scheduled to visit the kingdom. But their reluctance to let the United States know what was going on created significant tension between the two nations.

Tenet writes that it was reasonable to have expected the Saudis to pass the information along as soon as possible, but they did not.

After low-level discussions failed to produce a sense of urgency among the Saudis, Tenet flew to Riyadh to meet with Prince Naif, the interior minister and the man in charge of the Saudi secret police.

Tenet describes meeting with Naif in an opulent palace in Riyadh. He was accompanied by two colleagues, Deputy Director John McLaughlin and John Brennan, director of the CIA’s National Counterterrorism Center. Naif, by contrast, was joined by dozens of Saudi officials.

Tenet said he struggled to remain polite as Naif filibustered. Eventually, he had enough. He edged toward the prince, put his hand on his knee and asked, “Your royal highness, what do you think it will look like if someday I have to tell the Washington Post that you held out data that might have helped us track down al Qaeda murderers, perhaps even plotters who want to assassinate our vice president?”

Tenet told the prince he would be coming back each week to make sure intelligence flowed both ways.

Overall, however, Tenet makes it clear that he had warm relations with Saudi leaders. He says King Abdullah was instrumental in breaking logjam of the flow of intelligence and cites Naif’s son, the Saudis’ counterterrorism chief, as one of Washington’s best friends in countering al-Qaida.

Al-Qaida’s WMD plans
Tenet’s most frightening chapter is on al-Qaida’s plans to develop weapons of mass destruction, including nuclear weapons. It is titled “They Want to Change the World.”

Tenet writes that U.S. intelligence agencies “established that Al Qaeda had clear intent to acquire chemical, biological, radiological and nuclear weapons to cause mass casualties in the United States.”

According to Tenet, intelligence officials learned that Saudi extremist elements were planning to conduct a cyanide gas attack on the New York subway system in fall 2003 using a homemade device. But first, they requested permission from al-Qaida leaders.

“Chillingly, word came back from Ayman al-Zawahiri in early 2003 to cancel the operation and recall the operatives who were already staged in New York ‘because we have something better in mind.’ ”

Al-Qaida’s nuclear ambitions
It is the story of al-Qaida’s efforts to acquire weapons or weapons technology from Pakistan that anchors the most chilling part of that section.

The terrorist network made two separate efforts to persuade Pakistani scientists to provide it with nuclear weapons from their stockpile of about 50 nuclear weapons, highly enriched uranium and plutonium, and vast weapons infrastructure.

In 1998, Osama bin Laden, al-Qaida’s leader, was rebuffed, for unclear reasons. About two years later, he had better luck when al-Qaida reached out to a charity for Afghan refugees run by Pakistani nuclear scientists. Although some of the details of this effort have been previously reported, the extent of the effort went much further than what was publicly known.

In 2000, Tenet writes, the charity’s founder, Sultan Bashir-ud-Din Mahmood, and others at Pakistan’s nuclear weapons agency agreed to help Mahmood in his effort to share weapons of mass destruction with the Taliban leaders of Afghanistan.

In fact, Tenet said, U.S. intelligence learned that bin Laden and Mullah Mohammed Omar, the Taliban’s leader, had met with Mahmood and an aide in August 2001 in Afghanistan.

Tenet describes the initial Pakistani investigation as “ill-fated” and writes that the Pakistanis treated the charity officials with deference in their interrogations.

Showdown with Musharraf
So he went to Pakistan and met with Musharraf, warning about the outrage that would explode if it emerged that Pakistan was allowing nuclear scientists to help bin Laden acquire nuclear weapons.

Musharraf pooh-poohed the concerns, arguing that bin Laden and his associates were “men living in caves” who could not possibly take possession of such weapons, Tenet writes. Under interrogation, however, Mahmood subsequently confirmed the details of the August 2001 meeting with bin Laden.

At the same time, in the fall of 2001, Tenet writes, U.S. intelligence began picking up rumors from several reliable sources that a small nuclear device had been smuggled into the United States, for probable use in New York City. The Energy Department sent detection equipment to New York, he adds.

Tenet concludes that a nuclear detonation in a U.S. city is al-Qaida’s ultimate goal.

“I’m concerned this is where UBL and his operatives want to go,” he writes. “If they can arrange to set off a mushroom cloud, they make history. ... My deepest fear is that this exactly what they intend.”

Robert Windrem is an investigative producer for NBC News. Alex Johnson is a reporter for MSNBC.com.